Recoll vs X1 Search

Recoll is free desktop search software that finds documents by their contents and file names. It indexes many common document formats and compressed files, including email attachments nested inside archives. Search supports Boolean queries, phrases, proximity, wildcards, and filters for file type or directory tree. Indexing can run periodically as a batch job or continuously for real-time updates. Users can search through a Qt desktop interface, a web browser, the command line, GNOME Shell, KDE KIO, or KRunner; the browser interface queries a Recoll index. A Python 3 extension can query or update that index. Recoll can index PDF attachments and annotations, extract custom XMP metadata, and apply OCR to image-only PDFs using Tesseract or ABBYY FineReader. It supports multiple languages and UTF-8, and users can choose a stemming language at query time. Linux and source are free under the GPL. A contribution is requested for the Windows binary, but no amount is stated. Some formats on Linux and macOS need external applications or libraries, and the Windows port lacks some features, including multithreaded execution.

X1 Search has no write-up on Specifiction yet; its figures are above.